Rationale α1-Antitrypsin (AAT) deficiency is one of the commonest rare respiratory disorders worldwide. Diagnosis, assessment of risk for developing chronic obstructive pulmonary disease (COPD), and management of replacement therapy require the availability of precise and updated ranges for protein serum levels. Objective This paper aims to provide ranges of serum AAT according to the main genotype classes in the general population. Methods The authors correlated mean AAT serum levels with the main SERPINA1 variants (M1Ala/M1Val (rs6647), M3 (rs1303), M2/M4 (rs709932), S (rs17580) and Z (rs28929474)) in 6057 individuals enrolled in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) cohort. Results The following ranges (5th–95th percentile) of AAT were found in the serum (g/litre): 1.050–1.640 for PI*MM, 0.880–1.369 for PI*MS, 0.730–1.060 for PI*SS, 0.660–0.997 for PI*MZ and 0.490–0.660 for PI*SZ. There was very little overlap in AAT serum levels between genotype classes generally not believed to confer an enhanced health risk (MM and MS) and those associated with an intermediate AAT deficiency and a potentially mildly enhanced health risk (SS, MZ). Conclusion This work resulted in three important findings: technically updated and narrower serum ranges for AAT according to PI genotype; a suggestion for a population-based ‘protective threshold’ of AAT serum level, used in decision-making for replacement therapy; and more precise ranges framing the intermediate AAT deficiency area, a potential target for future primary prevention.

Alpha1-antitrypsin (AAT) deficiency, although largely under-diagnosed, is the underlying cause of approximately 1% of COPD cases. Lack of awareness leads to long delays in diagnostic testing. Subsequently, lifestyle and treatment choices with potentially positive effects on prognosis may be postponed. Data on the testing and diagnostic practices for AAT deficiency were derived from the University of Pavia, Italy, and the University of Marburg, Germany. In addition, a survey of physicians was undertaken to explore their awareness and attitudes toward AAT deficiency. In Pavia and Marburg, 125 and 729 patients, respectively, were identified with severe AAT deficiency between July 2006 and June 2011. The median time interval between the onset of symptoms and diagnosis was 6 years (interquartile range [IQR], 11; range, 0-40) and 7 years (IQR, 13; range, 0-73), respectively. Augmentation therapy was initiated almost immediately in Germany while treatment was delayed by 3 months in Italy (IQR, 5.25; range, 1-118). Survey data (Italy, n = 181; Germany, n = 180) revealed that pulmonologists had greater knowledge of AAT deficiency than internists and general practitioners, however, overall, only 18-25% of physicians tested all COPD patients. One-third of the respondents stated that they "sometimes" offered augmentation therapy to patients diagnosed with AAT deficiency. Major obstacles to AAT deficiency testing are physicians' attitudes and lack of understanding of the condition. A greater adherence to the guidelines that recommend diagnostic testing of all COPD patients, coupled with simpler testing protocols, may decrease delays and positively impact patient outcomes.

Background: Individuals with severe deficiency in serum α1-antitrypsin (AAT) concentrations are at high risk for developing chronic obstructive pulmonary disease (COPD), whereas those carrying the PI*MZ genotype are at slightly increased risk. Testing appropriate subgroups of the population for AAT deficiency (AATD) is therefore an important aspect of COPD prevention and timely treatment. We decided to perform an exhaustive investigation of SERPINA1 gene variants in individuals from the general population with a moderately reduced serum AAT concentration, because such information is currently unavailable. Methods: We determined the Z and S alleles of 1399 individuals enrolled in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) with serum AAT concentrations ≤1.13 g/L and submitted 423 of these samples for complete exon 2→5 sequencing. Results: We found that 900 of 1399 samples (64%), carried the normal PI*MM genotype, whereas 499 samples (36%) carried at least 1 SERPINA1 deficiency variant. In the subpopulations in which AAT concentrations ranged from >1.03 to ≤1.13 and from >0.93 to ≤1.03 g/L, individuals with the PI*MM genotype represented the majority (86.5% and 53.8%, respectively). The PI*MS genotype was predominant (54.9%) in the AAT range of 0.83 to 0.93 g/L, whereas PI*MZ represented 76.4% in the AAT range of >0.73 to ≤0.83 g/L. Conclusions: This analysis provided a detailed molecular definition of intermediate AATD, which would be helpful in the diagnostic setting.

With the aim of providing better clinical characterisation of patients with α₁-antitrypsin deficiency (AATD), we analysed the data of adult patients with severe AATD enrolled in the Spanish and Italian national registries.We assessed 745 subjects, 416 of whom were enrolled in the Spanish registry and 329 in the Italian registry. 57.2% were male and 64.9% were smokers or former smokers with a mean±sdage of 49.9±13.8 years. Most (81.2%) were index cases, mainly having the PI*ZZ genotype (73.4%), and the mean±sddiagnostic delay was 9.0±12.1 years.Patients with chronic bronchitis were younger, had better preserved lung function and lower tobacco consumption. Overlap patients (chronic obstructive pulmonary disease with asthma) were mainly females, more frequently never-smokers and received respiratory medications more often. 48% of emphysema, 27.5% of chronic bronchitis and 44.8% of overlap subjects were receiving augmentation therapy. Compared with PI*ZZ patients (n=547), the PI*SZ (n=124) subjects were older at diagnosis and had more preserved lung function, despite a higher mean smoking consumption.Early diagnosis of AATD is still an unmet need. Augmentation therapy is administered to similar proportions of patients with different clinical phenotypes. PI*ZZ patients in both registries had more severe respiratory disease than those with PI*SZ, despite lower smoking levels.

Alpha-1 antitrypsin (AAT) is the most abundant circulating antiprotease and is a member of the serine protease inhibitor (SERPIN) superfamily. The gene encoding AAT is the highly polymorphic SERPINA1 gene, found at 14q32.1. Mutations in the SERPINA1 gene can lead to AAT deficiency (AATD) which is associated with a substantially increased risk of lung and liver disease. The most common pathogenic AAT variant is Z (Glu342Lys) which causes AAT to misfold and polymerise within hepatocytes and other AAT-producing cells. A group of rare mutations causing AATD, termed Null or Q0, are characterised by a complete absence of AAT in the plasma. While ultra rare, these mutations confer a particularly high risk of emphysema. We performed the determination of AAT serum levels by a rate immune nephelometric method or by immune turbidimetry. The phenotype was determined by isoelectric focusing analysis on agarose gel with specific immunological detection. DNA was isolated from whole peripheral blood or dried blood spot (DBS) samples using a commercial extraction kit. The new mutations were identified by sequencing all coding exons (II-V) of the SERPINA1 gene. We have found eight previously unidentified SERPINA1 Null mutations, named: Q0cork, Q0perugia, Q0brescia, Q0torino, Q0cosenza, Q0pordenone, Q0lampedusa, and Q0dublin . Analysis of clinical characteristics revealed evidence of the recurrence of lung symptoms (dyspnoea, cough) and lung diseases (emphysema, asthma, chronic bronchitis) in M/Null subjects, over 45 years-old, irrespective of smoking. We have added eight more mutations to the list of SERPINA1 Null alleles. This study underlines that the laboratory diagnosis of AATD is not just a matter of degree, because the precise determination of the deficiency and Null alleles carried by an AATD individual may help to evaluate the risk for the lung disease.